EXISTS (or NOT EXISTS in this case) can be cleaner and more intuitive as to what it's doing over a join/is null check.

Using John's tables

SELECTb.id

, b.name

FROM@records r

join@books b on b.id = r.book_id

join@lists l on l.id = r.list_id

join@classes c on c.id = l.class_id

join@users u on u.class_id = c.id

whereu.id=1

and r.list_id=1

AND NOT EXISTS (SELECT 1 FROM @selection s WHERE r.book_id = s.book_id AND s.user_id = u.id)